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Signs Your Car Battery Is Going Bad


No one wants to get caught with a battery that is so dead that the car won’t start. Not only is this inconvenient to your day, but having to call roadside assistance can be expensive and having a friend come out and jump your car should be avoided if possible.

Thankfully, batteries do give off warning signs when they are on their way out. They don’t just usually fail out of no where, so be sure to listen to your car’s cries for help before you do end up stranded somewhere with a car that won’t start.

How Do I Know When My Car Needs A New Battery

You want to replace a battery before it leaves you stranded, but you also want to get your moneys worth out of the battery that you already have. So how do you know when it is time to replace your battery? You can test the voltage of the battery using a multimeter, or you can look for the telling signs of a bad battery.

If testing your car’s battery with a multimeter, the battery should be replaced at any voltage under 10. If you are wanting to just look for the signs the battery is deteriorating, you can do this by physically looking over the battery for bulging, leaking and corrosion. You can also pay close attention to the sound and patterns involved with your car’s starting behavior. Below we’ve listed 12 signs of a bad battery. Check them out for more information.

What Are The Signs Of A Battery Going Bad?

Here are the signs that your battery could go eminently. If you start to experience any of these, get your car to the mechanic or check your battery power using a multimeter.

  • Your Headlights Are Dimming
  • Slow To Crank
  • Clicking Sound When Turning Key In The Ignition
  • Pressing The Gas To Get It To Start
  • Engine backfiring
  • Electrical Issues
  • Check Battery Light Is On
  • The Battery Is Old
  • Warped Battery Case
  • Smells Sulfurous
  • Corroded Battery Terminals
  • Cold Weather

Headlights Are Dimming

The headlights are one of the electrical components of your car that are powered by the battery. When your headlights are dimming, it means that they are not getting sufficient power. This is not only a safety hazard (you need full powered headlights!!!!), it is also a telling sign that your battery is on its way out or that your electrical system is having issues.

Slow To Crank

If you drive your car regularly, you know what the normal sounds it makes are. Maybe you know it squeaks when turning left and you definitely know what a normal start for your car sounds like.

If that start begins to sound, well, a bit slow to you, it is worth looking into further. If it feels sluggish on the start, there is likely a good reason why and that reason is likely your battery, but should be investigated.

Clicking Sound When Turning Key In The Ignition

When you press your start button, or turn the key in the ignition, the car sends an electrical current to the starter solenoid. This is the first step in the starting process. The electrical current is sent using the car’s battery, and a dead battery will not be able to perform this task.

A failing battery will send a weaker current to the starter solenoid, which will cause you to hear a clicking sound.

Pressing The Gas To Get It To Start

If you can only get your car to start by gassing it, you likely have a failing battery. You shouldn’t have to do anything other than press the brake and turn the key in the ignition

Engine Backfiring

A failing battery can produce sparks, and will subsequently cause the car to backfire in some cases. This is a warning sign that you are sure not to miss, though a failing battery is just one of many issues that can cause a car to backfire.

Electrical Issues

The electrical system of your vehicle relies heavily on the battery. Components like the headlights, stereo, infotainment system, dashboard lights, in cabin lighting, windows and windshield wipers use the battery to have power.

If the electrical parts of your car aren’t functioning as quickly or are flickering on and off, your bad battery is likely to blame.

Check Battery Light Is On

So this one is pretty obvious, but if the dashboard of the car is displaying a battery symbol you need to look into what the issue is with the battery. Your car has hundreds of sensors that help it tell you when it is sensing something unusual. It is important to take all of these warnings seriously.

The Battery Is Old

Batteries have a limited life cycle. Your battery will not last forever and eventually will need to be replaced. If you are seeing some of the signs on this list in your car and your battery hasn’t been replaced in a while it is likely that it is time to spend some money on a new one.

How Long Do Car Batteries Last?

Car batteries can last as long as 10 years, though this is rare. On average, they last somewhere between 4 and 6. A car battery should always last at least 2 years.

How To Make Your Car Battery Last

A car battery will last longer if the vehicle is driven daily so that the battery is kept constantly charged. A car that is allowed to sit for extended periods of time will have its battery wear out sooner than one who is driven frequently. Car batteries can last up to 10 years though they usually only make it to about 5.

Warped Battery Case

As a battery ages, it starts to change shape. Hot and cold temperatures can help this process along considerably and make your battery warp prematurely. A warped battery can actually be somewhat dangerous as it can crack and spill its chemical contents within your car.

If your battery is misshapen, it is time for it to be responsibly discarded. You cannot just throw away a battery, they must be disposed of properly.

What Is The Proper Way To Dispose Of An Old Car Battery?

Many places that sell batteries also have initiatives to help you responsibly recycle your old one. Most mechanics will gladly take a used battery off of your hands and may even make money recycling it themselves. The laws on disposing a battery will vary from state to state, so check the guidelines for where you live through the local government.

Smells Sulfurous

If there is a sulfurous smell emerging from your car when you try to start it or open the hood, you likely have a leaking battery. Leaking batteries are caused by aging and warping, and in some cases an internal short- circuit. The battery will leak fluid that smells like rotten eggs or sulfur.

A leaking battery is a safety hazard and can corrode out parts of your engine that it comes in contact with. Make sure you take care to get the issue fixed as quickly as possible.

Corroded Battery Terminals

Other than old age, the most frequent reason that batteries need replacement is corrosion. The acid within the battery that helps give it power can leak out at the connectors. The acid will then harden and reduce the contact between the terminals and the connecting points. When this happens, it reduces that batteries ability to be recharged by the car’s alternator.

What Does Battery Corrosion Look Like?

Corrosion is very visible when looking at the battery. The terminals will have a blueish green powder build up around them. In some cases you can clean off this powder using the necessary safety precautions to extend the battery’s life, however it is a better idea just to recycle the battery and replace it.

Cold Weather

Freezing temperatures can wear out a battery prematurely. A car battery can be up to 35% weaker at sub freezing temperatures, but will still try to produce the same power output that it would if it were fully powered. What this does is it wears out the battery, weakening it permanently over time until it eventually fails.

In the case where the car gets really cold, to the point that the battery freezes entirely, it will likely need to be replaced. When a battery freezes solid it will likely be electrically dead and cannot be repaired or recharged. The battery will need to be replaced.

Telling The Difference Between A Bad Battery And A Bad Alternator

As we discussed earlier, the reason a vehicle might not be starting or is slow to start is usually an electric issue though it can have to do with the car not getting enough fuel in some cases.

What The Alternator And Battery Do In Your Car

An auto battery supplies a big electric charge that travels through the starting system and turns some gears to start the car. Once the car is running, the alternator sends current back to recharge the battery as you drive. It supplies power for your car’s electronics when you’re underway and makes sure the right amount of charge goes back to the battery.

Bad Battery Symptoms

If the engine cranking sounds sluggish you likely have a bad battery. If you’ve noticed the progression of your car turning over more and more especially on cold mornings, or just inconsistent starts then your issue is usually your battery needing replacing. Other symptoms include no interior lights and no sound. In some cases it isn’t the battery but the connection to the battery can be loose or corroded which will give you the same no power symptoms.

A jump start will only work if it is the battery that is your issue, so if you’ve successfully jumped your car then you know what your problem is. Luckily replacing the battery isn’t terribly expensive as far as car fixes go.

A Video Example Of What A Bad Battery Sounds Like

Signs of a Bad Alternator

The other major issue that is common in vehicle that won’t start is the alternator. Signs of a bad alternator include starting issues (duh that’s why we’re here), stereo output issues and dimming lights. If you can start your car with a jump, but your car stalls out while you are driving, it is probable that the alternator is not functioning properly and the battery is not being charged.

Another sign to look out for is a squealing noise when you are using electronic components such as the heater or the radio. This symptom points to an issue with the alternator bearings.

If the car won’t start but the headlights and other electrical components are working then the problem is likely the starter or a fuel issue.

How To Tell My Car Battery Is Bad Myself Using A Multimeter

What is a Multimeter?

A multimeter measures the voltage in parts of your car like the alternator and battery. It will show you the power outage in volts telling you how much power is currently stored in the battery.

Using a Multimeter to Test a Car Battery

  1. Turn the headlights and radio on for at least 3 minutes to get rid of any surface charge the battery may have.
  2. During those 3 minutes, you’ll set the multimeter to 15-20 volts.
  3. Turn off the electrical components of your car.
  4. Now, carefully connect the multimeter to the positive and negative battery terminals.

If you don’t have a voltage of around 12.6 volts, you may have a battery that needs to be replaced. At this point, start the car. You want to see a revised voltage over 10. If your voltage drops below 5 when the car is running, the battery is definitely bad and replacing it will solve your issues.

Tip: You can also test your alternator using a multimeter. The alternator should be putting out between 13 and 14 volts.

Battery Checks Through A Mechanic

When you get the car to the mechanic there are a few things that every mechanic should be looking over. They include:

  • Fluid level inspections
  • Corrosion check for cables and terminals
  • Cable connectivity check
  • Electronic battery test

An electronic battery test is what you are really here for, though all of these other services should also be performed by your mechanic to verify the safety and integrity of the battery. An electronic battery test will measure the cold cranking amps and the voltage of the battery.

The mechanic will also check the alternator’s voltage and output as well. Something the mechanic will look for are signs of bad diodes. These are the components that convert the electrical current from an alternating current into a direct current. If the diodes are bad you will need to replace the alternator.

How Much Does A New Car Battery Cost?

A car battery will cost on average $120 to $215 to replace. This cost is predominantly the cost of the battery itself, in fact the standard battery replacement is so simple that most mechanics will include a complimentary instillation in the price of purchase.

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